Add seeded task workspace creation

Current persistent tasks started with an empty workspace, which blocked the first useful host-to-task workflow in the task roadmap. This change lets task creation start from a host directory or tar archive without changing the one-shot VM surfaces.

Expose source_path on task create across the CLI, SDK, and MCP, add safe archive upload and extraction support for guest and host-compat backends, persist workspace_seed metadata, and patch the per-task rootfs with the bundled guest agent before boot so seeded guest tasks work without republishing environments. Also switch post--- command reconstruction to shlex.join() so documented sh -lc task examples preserve argument boundaries.

Validation:
- uv lock
- UV_CACHE_DIR=.uv-cache uv run pytest --no-cov tests/test_vm_guest.py tests/test_vm_manager.py tests/test_cli.py tests/test_api.py tests/test_server.py tests/test_public_contract.py
- UV_CACHE_DIR=.uv-cache make check
- UV_CACHE_DIR=.uv-cache make dist-check
- real guest-backed smoke: task create --source-path, task exec -- cat note.txt, task delete

docs/public-contract.md

@@ -46,8 +46,12 @@ Behavioral guarantees:
 - `pyro run`, `pyro env list`, `pyro env pull`, `pyro env inspect`, `pyro env prune`, and `pyro doctor` are human-readable by default and return structured JSON with `--json`.
 - `pyro demo ollama` prints log lines plus a final summary line.
 - `pyro task create` auto-starts a persistent workspace.
+- `pyro task create --source-path PATH` seeds `/workspace` from a host directory or a local
+  `.tar` / `.tar.gz` / `.tgz` archive before the task is returned.
 - `pyro task exec` runs in the persistent `/workspace` for that task and does not auto-clean.
 - `pyro task logs` returns persisted command history for that task until `pyro task delete`.
+- Task create/status results expose `workspace_seed` metadata describing how `/workspace` was
+  initialized.
 
 ## Python SDK Contract
 
@@ -106,6 +110,8 @@ Behavioral defaults:
 - `Pyro.create_task(...)` defaults to `vcpu_count=1` and `mem_mib=1024`.
 - `allow_host_compat` defaults to `False` on `create_vm(...)` and `run_in_vm(...)`.
 - `allow_host_compat` defaults to `False` on `create_task(...)`.
+- `Pyro.create_task(..., source_path=...)` seeds `/workspace` from a host directory or a local
+  `.tar` / `.tar.gz` / `.tgz` archive before the task is returned.
 - `Pyro.exec_vm(...)` runs one command and auto-cleans that VM after the exec completes.
 - `Pyro.exec_task(...)` runs one command in the persistent task workspace and leaves the task alive.
 
@@ -141,6 +147,8 @@ Behavioral defaults:
 - `task_create` defaults to `vcpu_count=1` and `mem_mib=1024`.
 - `vm_run` and `vm_create` expose `allow_host_compat`, which defaults to `false`.
 - `task_create` exposes `allow_host_compat`, which defaults to `false`.
+- `task_create` accepts optional `source_path` and seeds `/workspace` from a host directory or a
+  local `.tar` / `.tar.gz` / `.tgz` archive before the task is returned.
 - `vm_exec` runs one command and auto-cleans that VM after the exec completes.
 - `task_exec` runs one command in a persistent `/workspace` and leaves the task alive.